In the field of digital cameras, it is getting popular to get position data, data of latitude and longitude, of a camera location from the GPS (Global Positioning System), and memorize the position data in association with captured image data. An exemplar of such a digital camera is a camera phone with a GPS receiver. Also, a device for deducing the name of an imaged place or landmark from the attached position data has been suggested.
For example, Japanese Laid-open Patent Application No. 2003-209886 discloses a mobile terminal, a position information providing system and an imaging system, wherein a data base is provided for storing position information such as, latitudes and longitudes of places and landmarks, place-names and landmark names, data types, polygonal areas of named places and landmarks outlined by polylines, and letters for displaying the place-names and the landmark names. Based on the latitude and longitude of a location of a digital camera, position information of the camera location is retrieved from the data base, and a landmark name of the camera location is determined based on the retrieved information.
Japanese Laid-open Patent Application No. 2001-157098 discloses a camera device and a method for displaying camera position information, wherein a map is divided along longitudinal and latitudinal lines into a lot of areas, and a mesh number is allocated to each of the areas, so that landmarks located in the respective areas are stored in a memory in correspondence with the individual mesh numbers. Based on the latitude and longitude of a location of the camera device, the area in which the camera location exits is determined. Then, based on the mesh number of the determined area, a landmark name of the camera location is retrieved from the memory.
In the prior art disclosed in Japanese Laid-open Patent Application No. 2003-209886, however, it takes time for retrieval of the position information. This is because the retrieval of the position information from the data base is done based on the latitude and longitude of the camera location, while scanning even those landmarks as the object of searching, which are far distant from the camera location, e.g. those located in Hokkaido while the camera location is in Tokyo. According to the prior art disclosed in Japanese Laid-open Patent Application No. 2001-157098, all areas are scanned as the object of searching for the area where the camera location exits. Therefore, it takes certainly long time for the data retrieval.
Meanwhile, most of digital cameras stores captured image data in a storage medium, e.g. a memory card, so that captured images may be displayed on an LCD or the like based on the stored image data. Thus, the user of the digital camera can observe the captured image without the need for printing the image. Indeed image data is superior to photo-prints in view of preservation properties, but, with regard to efficiency of sorting and searching the images, the image data is inferior to the photo-prints, because the photo-prints may be put in order by filing them into albums or the like.
To improve the efficiency of sorting the image data, Japanese Laid-open Patent Application No.2005-107867 suggests an apparatus for and a method of making an album, wherein position data obtained from a GPS satellite is attached to image data, and geometrical ranges of respective camera locations of the stored image data are derived from the respective image data, so that the image data of many images are sorted according to the ranges of the camera locations.
According to an image sorting method disclosed in Japanese Laid-open Patent Application No.2003-271617, GPS data, i.e. position data obtained from a GPS satellite, are attached to each image file, and different folders are prepared for different GPS data, so that the image files are sorted according to the attached GPS data and stored in the corresponding folders.
However, if position data obtained from the GPS satellite is inaccurate because of a low GPS function, and thus a wrong place-name or landmark is selected, the image data will be sorted wrongly. In the prior arts, it is impossible to change the results of sorting afterward.